Contamination of water with potentially hazardous materials is a common problem facing industry, the government and the general public. As a result of spills in waterways, leakage from storage facilities and surface discharges, contaminants are slowly destroying our water supply. Such contaminants may further enter our water supplies via subsurface soil and/or rock formations and eventually percolate into the groundwater. There are over two hundred organic and inorganic chemicals which have been identified in various groundwater supplies alone. Such ground water is the principal source of municipal water, agricultural irrigation, and water used by industry. There is thus a consistent health threat to our drinking water supplies. In addition, chemical discharging into intercoastal waters has resulted in damage to marine life as well as to marine ecosystems.
It is a fairly common occurrence to find such contaminants in our nation's lakes and rivers as well as the surrounding oceans. The amount of unlawful dumping of such wastes is increasing in the waters of the United States. Our groundwater, drinking water and waste water continues to be jeopardized as such activities continue. Useful methods of ascertaining the source of such pollutants into our waterways is essential.
Clearly there is a longfelt need by the public for a safe technique for "serializing" or "fingerprinting" petroleum, petroleum products and bulk chemicals in storage or transit so that responsibility for dumping, spilling or leakage of such chemicals can be appropriately determined. There is also a need for serializing bulk adulterants such as cyanides which are sometimes placed in foods and medicines by disturbed people to aid in apprehending such people. There is also a longfelt need by the petroleum and chemical industry for safe techniques to serialize oil and other chemical products for internally auditing the transfer of such products to prevent and/or prove theft.
It has been proposed to use radioactive materials as tracers in fluids. However, the use of radioactive materials for fingerprinting liquids would not be totally satisfactory. The consumption of petroleum products containing radioactive tracers, for example, would result in their uncontrolled release into the environment. It has also been proposed to use certain non-radioactive tracers in reservoir characterization studies to determine fluid residence times and conductive fluid flow paths. However, in such applications, the tracer is detected in salt water. Salt water is a very simple chemical composition and it is easy to obtain a low detection threshold because there are not many interfering materials. However, our proposals to label crude oil and other chemical materials with low levels of non-radioactive tagging agents have been met with skepticism because of the presumed difficulties in detecting such tagging agents. We have found that it is not difficult to identify many non-radioactive materials at very low levels if one knows what one is looking for.